1. Field of the Invention
The present invention relates to a thin type keyboard switch with tactile feedback.
2. Description of the Prior Art
Generally, membrane contacts are formed by as shown in FIG. 4, two pieces of flexible stamped plates (3). A spacer (2) interposed laminated on a rigid frame (1) such as metal with upper and lower contacts (5) facing each other at the portion of hole (4) located in the spacer (2).
In a conventional key switch for turning each membrane contacts on or off, as shown in FIG. 4, a rubber reversing plate (6) is laminated so as to be relatively thin at a surrounding portion and to form a pressing projection (8) only at the center portion on the lower face of a bulge (7) at every contact of such rubber reversing plate (6). 4 depressing barrel (11) is depressed through a coil spring (10) by pressing a key top (9), thereby bringing membrane contacts (5) together by the pressing projection (8) of the rubber reversing plate (6).
As to a conventional keyboard switch for pressing the membrane contacts, the height of the bulge (7) of the rubber reversing plate (6) was very high. This height increase the thickness of whole of the keyboard switch and resulted in a hindrance to realize the thin keyboard switch. Further, as for the rubber reversing plate (6), if the bulge (7) was depressed for a fixed distance, peripheral portion (13), being relatively thin, was reversed. But, since the material of the reversing plate was rubber, the user could not feel the clear click feeling at the tip of finger when the keyboard was depressed.
A first object of the present invention is to obtain a thin key board switch in which the height of whole of a keyboard switch is restrained.
A second object of the present invention is to obtain an improved keyboard switch having a clear operating tactile feedback feeling at the time of depressing a key top, and which can achieve the stable conductivity at the membrane contacts.
A third object of the present invention is to obtain a keyboard switch having simple reversing plate structure with low cost.
A fourth object of the present invention is noiseless key board switch implementing by interposing a synthetic resin cover or a cloth having the effect of absorbing noise between a reversing plate and a depressing barrel of the key top.
Still other objects and advantageous features of the present invention will be presented in the following description.